Machine for automatically attaching cover slips to microscope slides

ABSTRACT

A machine is provided for automatically attaching cover slips to microscope slides having specimens for microscopic examination, including a first magazine for microscope slides, a second magazine for cover slips, and a reciprocating transport means for transport of slides and cover slips from the respective magazines to a working station. The apparatus further includes a pump for application of adhesives to slides, and a lifting means for lifting and placing of a cover slip on a slide which is provided with adhesive. The two magazines are located on opposite sides of the transport means, and that the transport means is arranged to carry a slide from the first magazine to the working station in an outgoing movement from a home position, and to carry a cover slip from the second magazine to the working station in a return movement. The lifting means is arranged to lift a cover slip from the transport means before the latter is allowed to start its outgoing movement, and further is arranged to place a cover slip on the slide on the working station with terminated outgoing movement of the transport means and after application of adhesive to the slide by the pumping means. The transport means is arranged to bring the slide with attached cover slip back to the first magazine during its return movement, at the same time as a new cover slip is carried from the second magazine to the working station.

BACKGROUND OF THE INVENTION

The invention relates to a machine for automatically attaching coverslips to microscope slides having specimens for microscopic examination,comprising a first magazine for microscope slides, a second magazine forcover slips, and a reciprocating transport means for transport of slidesand cover slips from the respective magazines to a working stationcomprising a pumping means for application of adhesive to slides, and alifting means for lifting and placing of a cover slip on a slide whichis provided with adhesive.

Such application of cover slips or cover glasses to microscope slidesespecially is carried out in hospitals and in medical laboratories,wherein microscope slides having different types of medical specimensmust be covered by protective cover slips. The tissue specimens whichare to be examined, are either histologic specimens in the form of thincuts (3-4 μm thick) or cytologic smears. Both types of specimens arecoloured in a stainer prior to sealing in order to bring out the cellstructure. In this connection it is usual to make use of a basket whichcontains a number of slides, as a carrier during the staining as well asthe sealing process.

On the market there exist several types of machines or apparatusescarrying out gluing of cover slips on slides. An apparatus or machine ofthe type stated in the introduction is, for example, known from theinternational patent application No. PCT/NO93/00188 (WO 94/14097). Inthis apparatus, a slides magazine is arranged next to a cover slipsmagazine, and a reciprocating sliding means provides for simultaneousfeeding of a slide and a cover slip to a position next to each other ona working station where the cover slip is placed on the slide afterapplication of adhesive thereon. The cover slips magazine here consistsof a wall-forming frame member surrounding a stack of cover slips whichare all the time supported by the sliding means, the sliding meanshaving a recess which, in an initial position, receives the lowermostcover slip in the stack, so that the sliding means brings individualcover slips to the working station. Since the stack of cover slips aresupported by the sliding means, the stack will remain on the slidingmeans if the magazine frame member is lifted therefrom. Accordingly, aloaded cover slips magazine here is not a separate unit which is able tobe exchanged and replaced by another preloaded cover slips magazinecontaining a different cover-slip size.

In machines and apparatuses of the topical type it is important that theperiod from the time when the tissue specimens are taken out from thecolouring process until they are sealed, is as short as possible. Adehydration of the specimens results in a poorer sealing and readabilityof the tissue condition, air bubbles then arising in the tissue. Inother words, it is important that the machine works as quickly aspossible. Further, there are several laboratories which use differentcover-slip sizes, and a rapid change from one cover-slip size to anotherhere is of great importance. A cover-slip attaching apparatus of thetype utilizing tape for sealing, does not have said drawbacks, theapparatus working very quickly and not being dependent on cover slips ofa certain size. However, in addition to being prone to gettingscratches, the tape has the drawbacks that it is not planar if thetissue specimen is not planar, and that in some cases it has a tendencyto loosen over time. Therefore, there is a clear tendency that more andmore laboratories want to use cover slips which are manufactured fromglass. It is important that the cover slip is placed in the glue with avery calm movement and such that air bubbles are not captured under thecover slip.

In addition to the fact that the known machines and apparatuses on themarket do not have such a high working speed as desirable, the arerelatively big. Further, they have a poor accessibility for removal ofglue and glass residues and for other maintenance which is necessary

SUMMARY OF THE INVENTION

It is an object of the invention to provide a machine of the topicaltype having such a high working speed that microbubbles are avoidedwithout additional wetting of the tissue with unnecessary solvent beingnecessary, at the same time as one avoids getting air bubbles in thetissue.

Another object of the invention is to provide such a machine whichenables a rapid change from one cover slip size to another.

A further object of the invention is to provide a machine which is verysmall and compact and also silent-running, and which has such a designthat the user is protected against glass fragments which may spatteraround in case of accidental crushing of cover slips, as well as againstinhalation of solvent gases.

A still further object of the invention is to provide a machine having aconstruction giving good accessibility for daily cleaning, operation andservice, in order to achieve a substantial improvement of theoperational security.

For achieving the above-mentioned objects there is provided a machine ofthe introductorily stated type which, according to the invention, ischaracterized in that the two magazines are located on opposite sides ofthe transport means, and that the transport means is arranged to carry aslide from the first magazine to the working station in an outgoingmovement from a home position, and to carry a cover slip from the secondmagazine to the working station in a return movement, the lifting meansbeing arranged to lift a cover slip from the transport means before thelatter is allowed to start its outgoing movement, and further isarranged to place a cover slip on the slide on the working station withterminated outgoing movement of the transport means and afterapplication of adhesive to the slide by the pumping means, the transportmeans being arranged to bring the slide with attached cover slip back tothe first magazine during its return movement, at the same time as a newcover slip is carried from the second magazine to the working station.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be further described below in connection withexemplary embodiments with reference to the drawings, wherein

FIG. 1 shows a front view of a machine according to the invention,wherein some details are omitted to expose and show other details;

FIG. 2 shows the machine in FIG. 1, as viewed from above and with somecomponent parts omitted;

FIG. 3 shows an end view of the machine in FIGS. 1 and 2, as viewed fromthe left;

FIG. 4 shows an end view corresponding to FIG. 3, but with the end wallremoved to show internal details of the machine;

FIG. 5 shows a vertical cross-sectional view of the machine and shows alongitudinal section through the pumping means of the machine and itsassociated motor drive means;

FIG. 6 shows a view of the machine in FIG. 1, as viewed from behind andwith the back cover of the machine removed;

FIGS. 7 and 8 show plan views of a carrier plate on the transport means,with a gripping finger shown in two different operating positions;

FIGS. 9 and 10 show a front view and a plan view, respectively, of asection of the machine in FIG. 1 (with some parts omitted), and show thetransport means in the home or fetching position;

FIGS. 11 and 12 show a front view and a plan view, respectively, of asection of the machine (with some parts omitted), in a mannercorresponding to FIGS. 9 and 10, but with a slide in a pulled-outposition;

FIG. 13 shows a longitudinal section of the pumping means correspondingto that of FIG. 5, but with a connected glue container and a gluedispenser, and with a connected solvent container;

FIG. 14 shows a front view of the pumping means, in a plane at rightangles to the sectional plane in FIG. 13;

FIGS. 15A, B and C show front views of the pumping means, in the way itis shown in FIG. 14, in three different operating positions; and

FIG. 16 shows a longitudinal section of the pumping means on a somewhatenlarged scale.

DETAILED DESCRIPTION OF THE INVENTION

As appears from FIGS. 1-6, the shown embodiment of the apparatus ormachine 1 according to the invention has a generally box-like shape andis divided into a rearward and a forward main chamber 2 and 3,respectively, by means of a longitudinal, vertical partition wall 4forming a support for most of the units and component parts of themachine. The rearward main chamber 2 is closed and contains all motorsused for operation of the machine, and also all electronics including aprocessor unit for controlling the operation of the machine, and a powersupply. The forward main chamber 3 on the front side is shielded by atransparent sliding door 5 which may also be lifted completely off formaximum accessibility. This chamber contains as main elements a firstmagazine 6 (also called slides magazine) for receiving at least onebasket 7 for slides 8, a second magazine 9 for receiving a stack 10 ofcover slips 11, a reciprocating means 12 for transport of slides andcover slips from the respective magazines 6, 9 to a working station 13,a pumping means 14 arranged on the working station for application ofadhesive/glue on slides, and a lifting means 15 for lifting and loweringof cover slips on the working station.

Further, at the right side of the forward main chamber 3, there isarranged a glue container 16 which is connected to the suction part ofthe pump (see FIGS. 13 and 14), and on the left side, next to the coverslips magazine 9, there is placed a transparent, detachable solventcontainer 17 the function of which is to be further described inconnection with FIGS. 13 and 14. The glue container 16 is exposed whenthe above-mentioned sliding door 5 is in a left end position, whereasthe solvent container 17 and the cover slips magazine 9 are exposed whenthe sliding door is in a right end position. In the chamber 3 there isalso arranged a fan 18 providing for venting of solvent gases via a hoseconnection 19.

As appears from the FIGS. 1 and 9-12, the two magazines 6, 9 are locatedon opposite sides of the transport means 12, this being arranged tocarry a slide 8 from the slides magazine 6 to the working station 13 inan outgoing movement from a fetching or home position, and to carry acover slip 11 from the cover slips magazine 9 to the working station ina return movement to the home position. Thus, the transport means goesin “shuttle traffic” between the two magazines 6 and 9. The arrangementis such that the transport means brings a slide with an attached coverslip back to the slides magazine during its return movement, at the sametime as a new cover slip is carried from the cover slips magazine to theworking station. Since the shuttle movement is carried out continuously,without any waiting time, there is achieved a machine with a very highworking speed.

The transport means 12 comprises a carriage 20 which is displaceable ona pair of horizontal guide rods 21, 22, and which is pulled back andforth between the magazines 6 and 9 by means of a tooth belt 23. Thetooth belt runs over a pair of guide rollers 24, 25 and is driven by acarriage motor 26 (shown stippled in FIG. 6). The rotation of thecarriage motor is transferred to the tooth belt 23 via a transmissionmeans comprising a tooth belt wheel 27 on the motor shaft, an additionaltooth belt 28 and an additional tooth belt wheel 29 on a shaft 30 on theforward end of which there is fixed a driving gear wheel (not shown)which is in engagement with the tooth belt 23. The shaft is supported inthe same manner as shown in FIG. 4 for the transmission shaft for thepumping means 14, and a corresponding arrangement is also used for theother driving motors, all the motors as mentioned being installed in therearward main chamber 2 of the machine.

At the top of the carriage 20 there is mounted a transport or carrierplate 31. The function of this plate is to provide for pulling-out orextraction of a slide 8 from the slides magazine 6 during the outgoingmovement of the carriage 20, and also to carry a cover slip 11 from thecover slips magazine 9 to the working station 13 in the return movementof the carriage. The dimensioning of the components and the mutualdistance between the working station and the cover slips magazine areadapted in such a manner that the carrier plate 31, at the end point ofthe outgoing movement of the carriage, has brought a slide to thecorrect position on the working station, at the same time as the carrierplate then is situated in the correct position for carrying along acover slip from the cover slips magazine in the return movement of thecarriage.

The slides magazine 6 is designed for receiving at least one basket 7having a number of horizontal shelves for support of a correspondingnumber of microscope slides 8. The magazine is provided with verticalslide profiles 35 ensuring that the baskets can be inserted only withthe correct orientation in the magazine. On the side facing away fromthe working station 13, the baskets are provided with teeth 36 forengagement with corresponding teeth on a small toothed wheel 37 which isarranged to be rotated by a feeding-down motor 38, so that the basketscan be fed down stepwise one tooth position, to successively bring a newslide into position for extraction in normal operation of the machine.The magazine is also provided with sensors (not shown) to sense if abasket is present, and to register that a basket is completely fed downand falls down from the magazine.

The feeding-down toothed wheel 37 sits on a shaft 39 which is coupled tothe motor 38 through a similar transmission as the one described inconnection with the carriage motor 26. As shown in FIG. 6, on the toothbelt wheel on the shaft 39 there is mounted a signal disc 40 for controlof the rotational movement of the motor, as further described later.

The cover slips magazine 9 is a unit which is arranged for detachablemounting in the machine, so that one is able to carry out a quickreplacement and put in place other cover slips magazines which arepossibly dimensioned for other cover slip sizes. As regards themicroscope slides, these normally have only one size, viz. 76×26×1 mm(3″×1″×{fraction (1/25)}″), whereas the cover slips are 24 mm wide and0,15 mm thick, and can have a length of 40, 50, 55 or 60 mm.

The machine is provided with sensors (not shown) sensing the dimensionof the cover slips magazine inserted in the machine, and providing forpossible necessary readjustment of the control functions of the machine,so that this is operated in the correct manner, in accordance with thechosen cover slip size. As will be appreciated, the cover slip lengthhas an influence on the length of the return movement of the carriage 20and on the length of the glue stripe which is pumped out onto a slide onthe working station 13, as mentioned in connection with the descriptionof the manner of operation of the machine. As described later, theseparameters can be chosen in a so-called parameter list in associationwith the operating menu of the machine, or they may be chosen by meansof the above-mentioned sensors by means of which the machine “senses”which cover slips magazine is inserted in the machine.

As appears from FIGS. 1 and 2, the cover slips magazine 9 is defined bya forward and a backward end wall 45 and 46, respectively, and twoparallel side walls 47 and 48. The bottom of the magazine is open exceptfor a pair of edge flanges 49, 50 extending along the lower end edges ofthe side walls 47, 48 and forming a support for the cover slips stack 10in the magazine. When placing a new magazine in the machine, this isguided in place by means of a pair of guide pins 151 (only one is shown,see FIGS. 9 and 11) providing for an accurate positioning of themagazine. The magazine may for example, be fixed with a simple screw, orby means of a pair of permanent magnets 152 as shown, for even morerapid magazine change.

The cover slips magazine is designed and positioned to cooperate withthe carrier plate 31 which is shown in detail in FIGS. 7 and 8. Saidedge flanges 49, 50 have a somewhat lower level than the upper surfaceof the carrier plate, and a mutual distance allowing introduction of arearward part 51 of the carrier plate therebetween. The rearward part 51at its free end is formed with an inclined plane 52 for lifting of thecover slips stack 10 in the cover slips magazine when introducing saidpart 51 into the magazine, and with a gripping edge 53 adjacent to theinclined plane having a height corresponding to the cover slipthickness, so that only one cover slip 11, which falls down in front ofthe gripping edge when the part 51 of the carrier plate is introducedinto the magazine, is pulled out from the magazine in the returnmovement of the carrier plate. The lower edge 54 of the forward end wall45 of the magazine is located at such a level above the carrier plate 31that the remaining cover slips in the stack are kept back in the returnmovement, and the remaining cover slips will sink onto the edge flanges49, 50.

The rearward end wall 46 of the cover slips magazine at its lower edge55 is formed with a narrow depending portion corresponding to a recessor slot 56 in the rearward part 51 of the carrier plate 31, so that thelowermost cover slips in the stack 10 will not be pushed out from themagazine when the rearward part 51 is introduced into the magazine andlifts up the cover slips.

At its forward end the carrier plate 31 is provided with a fixedgripping rest 57 and with a pivotally mounted gripping finger 58 havinga forward end which is adapted for gripping and pulling-out of slides 8from the slides magazine 6. At its rearward end the gripping finger 58has a downwards extending pin 59 (see FIG. 4) which is adapted to beinfluenced by the armature of an electromagnet 60 fitted on the carriage20. The gripping finger also constitutes a sensing means for sensingwhether a slide is present in a feed-out position when the transportmeans 12 is in its home position. If the gripping finger “finds” a slidewhen it is in its home position in the magazine 6 and is influenced bythe electromagnet 60, the slide will be retained by the gripping finger,and after a short time-out period, under the control of the processorunit of the machine, the machine will proceed in its working cycle, asfurther described later. On the other hand, if the gripping finger doesnot find a slide during the first part of its turning movement, it willcontinue its movement under the influence of the electromagnet, and thenactuate a microswitch 61 fitted on the underside of the carrier plate31. The actuation of the microswitch will entail that the grippingfinger 58 returns to the open position, and in addition that the motor38 for feeding-down of baskets starts and feeds down the basket 7 in themagazine one step. This operation is repeated until the gripping fingerfinds a slide. The machine thereafter carries out some workingoperations associated with the lifting means 15, and which will befurther described below, and thereafter the carriage 20 is started andthe carrier plate 31 carries a slide 8 to the correct position on theworking station on a rail 62 (see FIG. 12) functioning as a sliding basefor the slide.

The lifting means 15 for lifting and lowering of cover slips 11comprises a pair of suction cups 65, 66 fitted in a suction cup head 67,so that they have—or may be positioned in—a suitable mutual distance forgripping of the end portions of a cover slip. At the lower ends of thesuction cups there is arranged an abutment member 68 which preferablyhas a downwards convexly curved, resilient abutment surface, so that thesuction cups when activated pull up the cover slips to a slightly curvedposition resting against the abutment surface. As appears, the suctioncup head 67 is fixed to a lifting block 69 which is slidable on a pairof vertical guide posts 70, 71 and is spring-loaded downwards by meansof a spring 72.

The suction cups 65, 66 are connected to a vacuum cylinder 73 in theform of a so-called “twist cylinder” which is coupled to a vacuum motor74 through a transmission of a design corresponding to that describedabove in connection with the carriage motor 26. The internal volume ofthe twist cylinder 73 communicates with a vacuum watch 75 delivering asignal if a vacuum is obtained between the twist cylinder and thesuction cups after start of the vacuum motor 74 when the gripping finger58 has gripped a slide in the feed-out position, as further described inconnection with the manner of operation of the machine. When a vacuum isobtained, this means that a cover slip is present on the workingstation, and that this is retained by the suction cups.

The lifting means further comprises a lifting motor 76 which, through atransmission means of the above-mentioned type, is coupled to thelifting block 69 via an eccentric means 77 which also comprises aneccentrically placed ball bearing 78, as shown in FIG. 4. When a vacuumis obtained, the lifting motor provides for lifting of the suction cuphead with the retained cover slip from the carrier plate 31. Saideccentric means causes the lifted cover slip, when the transport meanshas completed its outgoing movement, to be lowered onto the slide with asinusoidal movement, so that the cover slip hits the glue on the slidewith a relatively slow motion. The eccentric means is constructed in amanner corresponding to that of an eccentric means for the pumping meanswhich is to be further described below.

The pumping means 14 with associated motor drive means is shown in FIG.5, and further details of the pumping arrangement are shown in FIG.13-16. The pump proper is a cylinder/piston unit consisting of acylinder 85 and a piston 86 which are fixedly mounted in a housing 87fixed to the partition wall 4. The pumping means is connected to theglue container 16 via a hose 88 which is connected to the lower end ofthe cylinder 85 through a check valve 89. The piston 86 is provided witha central passage 90 which, through an upper opening 91 and a hose 92,is connected to a glue dispenser 93 which is fixed to the suction cuphead 67 of the lifting means by a bracket 79.

In the housing 87 there is also fixedly mounted a solvent container 94for receiving a glue-dissolving solvent, e.g. xylene. The solventcontainer 94 communicates with the pump cylinder 85 through a channel95, and it is further connected to the transparent and detachablesolvent container 17 via a hose 96. At its upper end the fixed container94 is provided with a spring-loaded closing valve 97.

The glue dispenser 93, which opens through an internal check valve (notshown), is fitted in such a position on the suction cup head 67 that itsoutlet end is moved down into the solvent in the solvent container 94via the closing valve 97 when the suction cup head with the bracket 79is lowered to its lower position. Thus, the solvent in the container 94serves both to keep the dispenser outlet open and to prevent the piston86 from being glued to and stuck in the cylinder. The transparentcontainer 17 serves both as a level control and for filling and emptyingof the fixed solvent container 94. The carrier plate 31 has a suitableopening 80 (FIGS. 2 and 10) or slot 81 (FIGS. 7 and 8) allowing thedispenser 93 to be lowered into and lifted from the solvent container94.

The pumping means is driven by a pump motor 98 which is mounted in therearward main chamber 2, as shown in FIGS. 5 and 6. The pump motor iscoupled to the pump unit 85, 86 through a transmission means comprisinga tooth belt wheel 99 on the motor shaft, a tooth belt 100 and anadditional tooth belt wheel 101 which is fixed on one end of a driveshaft 102 of which the other end is coupled to an eccentric means 103driving the pump. The drive shaft 102 is mounted by means of ballbearings in an intermediate block 104 which is fastened between thepartition wall 4 and a mounting plate 105 in the rearward chamber 2.

The eccentric means 103 comprises an eccentrically mounted wheel 106placed in a guide recess 107 in a yoke 108 which is connected to thepiston 86. The initial position of the eccentric means is a horizontalposition (3 o'clock) as shown in FIG. 15A. When starting the pump motor98, this is controlled so that it rotates half a stroke backwards, forinstance to a position of the eccentric wheel corresponding to oneo'clock as shown in FIG. 15B, and half the set glue quantity then issucked into the cylinder. As described later in connection with themanner of operation of the machine, the other half of the set gluequantity has been sucked in at an earlier stage of the operation. Thewhole pump stroke then is carried out in that the pump motor rotates theeccentric wheel in the opposite direction to 5 o'clock (i.e. 120°), asshown in FIG. 15C, and the glue in the cylinder 85 then is pumped out inthat the yoke with the piston 86 is pressed down. Because of the checkvalve 89 in the cylinder, the glue is pressed upwards through thepassage 90 in the cylinder and into the hose 92 leading to the dispenser93.

As mentioned above, all the illustrated motors 26, 38, 74, 76 and 98 areinstalled in the rearward main chamber 2 of the machine. The used motorsare digitally controlled step motors. The rotational movement of themotors is controlled in that the motors are supplied with pulse trainshaving a desired number of pulses and having a desired polarity from acentral processing unit (CPU) in the form of a microprocessor. Thepolarity of the pulses determines the rotational direction.

The processor unit is mounted on a CPU board 115 in the main chamber 2.As appears from FIGS. 4 and 6, the rearward chamber also contains themain switch 116 of the machine, a power supply 117, an electronics plate118 comprising the electronic circuitry of the machine, and a driverboard 119 for the step motors. The ON/OFF button 120 and a cableconnection 121 of the main switch are shown in FIG. 3.

The start and stop positions of the motors are controlled by means ofsignal discs which are adjustably mounted on the driving shafts of thetransmission means for the motors, and which cooperate with fixedlymounted photo-cell sensing means in the form of so-called read forks. InFIG. 5 such a read fork 125 is shown in connection with a signal disc126 on the tooth belt wheel 101 on the transmission shaft 102 of thepumping means. (It is to be noted that the read fork for this signaldisc is shown to be mounted in a different position in FIG. 6.) In FIGS.4 and 6 a corresponding read fork 127 is shown to be mounted inconnection with the signal disc 128 for the drive motor 76 of thelifting means. Corresponding read forks and signal discs are shown inconnection with the feed-down motor 38 and the vacuum motor 74. Asregards the carriage motor 26, the start/stop position thereof iscontrolled by a read fork 129 mounted on the partition wall 4 inconnection with a tongue 130 extending downwards from the carriage 20.

The signal discs for the motors 74, 76 and 98 are shown as circulardiscs, but are in practice formed with part-circular sector portionshaving a different radius, so that the light from the respective sensorphoto-cell is interrupted in the desired rotational position of thedisc.

As regards the signal disc 40 for the basket feed-down motor 38, this iscircular as shown in FIG. 6, but is provided along its periphery witheight radial slots 131 having an angular distance of 45°, a rotation ofthe feed-down toothed wheel 37 of 45° corresponding to a basketfeeding-down of one step, i.e. the distance between two slides shelvesin the basket in question.

A control panel 132 for operation of the machine is arranged on theupper side thereof as shown in FIG. 2, and comprises a switch panel 133having a number of buttons allowing the necessary settings andoperations, and a display 134 giving information about the status of themachine and showing error messages in case of irregularities ormalfunctions.

All the movements of the machine are controlled digitally by means ofthe microprocessor which is based on counting of pulses for control ofthe step motors and for measuring chosen timeout periods regulating thetime for start of the various operations. The number of pulses and thedesired time intervals can be chosen quickly in the menu of the machinewith the associated parameter list, i.e. a list of parameters which aredecisive for the operations of the machine. By a suitableprogramming/setting of the pulse number for stop of each motor motion,based on test runs of the machine, the operations thereof can byadjusted and performed very accurately.

The manner of operation of the machine will be described below inconnection with a normal operating sequence.

After the placing of a basket 7 in the slides magazine 6, the machinestarts automatically after 2 seconds if the start button has not alreadybeen depressed. The gripping finger 58 is operated by the electromagnet60 and grips a slide 8. If a slide is not present, the gripping fingeris opened and the basket is fed down one step. After a short timeinterval (0,1 s) the vacuum motor 74 starts and rotates the twistcylinder 73 (ca. 200°), so that a certain vacuum is created in thevolume between the twist cylinder chamber and the suction cups 65, 66resting against the cover slip 11 on the working station 13. When thevacuum watch 75 acknowledges a vacuum, the lifting motor 76 starts andcauses lifting of the suction cup head 67 with the cover slip and theglue dispenser 93 to a suitable height above the carrier plate 31.Simultaneously the pump motor 98 rotates half a stroke backwards, sothat half the set glue quantity is sucked into the cylinder 85.Thereafter the carriage motor 26 starts, and the carrier plate 31 startspulling out the slide 8 from the magazine 6, and in the correctly setposition of the slide the pump motor 98 starts in the opposite directionand glue is pumped out via the dispenser 93, so that the set gluequantity is pumped out along the centre line of the slide and in a setlength during the outgoing movement of the slide. The eccentric means103 causes that one gets a symmetrical, slightly “boat-shaped” gluequantity with most of the glue in the middle and a decreasing gluequantity in the direction towards the end edges of the slide. When thecorrect outgoing movement of the carrier plate 31 is achieved, the coverslip will “hang” in the correct position above the slide, at the sametime as the left or rearward part 51 has arrived at the correct positionfor pulling out a new cover slip from the cover slips magazine 9 in thereturn movement. The lifting means is now lowered so that the cover slipis placed in the glue on the slide. By means of the eccentric means 77the cover slip is lowered with a sinusoidal movement, so that the coverslip hits the glue with a relatively slow motion. Since the cover slip11 is lowered in a slightly curved condition as mentioned above, the“boat-shaped” configuration of the glue quantity with the highest pointin the middle will contribute to enhancing the pressing-out of the glueand possible air bubbles towards the ends.

After the lifting means has been lowered, the vacuum motor 74 startsonce more, but in the opposite direction, so that the twist cylinder 73rotates approximately 70° in the opposite direction from its homeposition. Thereby the vacuum is reduced and replaced by a smalloverpressure, so that the suction cups release the cover slip.Thereafter the lifting means goes up again, so that the suction cups arelifted clear of the cover slip, and the carrier plate returns to itshome position and brings along a new cover slip to the lifting positionat the same time as the finished sealed slide is pushed back to theshelf in the basket. The pump piston 86 is lifted back to itsintermediate position, another half glue quantity being sucked in fromthe glue container 16. The feed-down motor 38 starts and feeds down thebasket one step, and in this manner the operation continues until thebasket falls down from the magazine and is registered by an opticalsensor.

At the same time as the basket 7 is fed down one step, i.e. one toothposition, the lifting means 15 is lowered, so that the suction cups 65,66 are pressed against the new cover slip which is placed on the workingstation 13. Simultaneously, the glue dispenser 93 is dipped into thesolvent container 94, and remains therein until a new slide is found bythe gripping finger 58.

If a vacuum is not obtained when the vacuum motor 74 starts and thetwist cylinder 73 is rotated, this means that a cover slip is notpresent on the carrier plate 31. This will be the case at the firststart of the machine. This results in that vacuum is disconnected andthat the transport means 12 effects a movement cycle to carry a coverslip from the magazine 9 to the working station 13. Thereafter themachine is started again, as described above. If a vacuum is notobtained either in this case, the machine interprets this to mean thatthe cover slips magazine is empty and shows the message “Load coverglass” in the display of the control panel.

What is claimed is:
 1. A machine for automatically attaching cover slipsto microscope slides having specimens for microscopic examination,comprising a first magazine for microscope slides, a second magazine forcover slips, and a reciprocating transport means for transport of slidesand cover slips from the respective magazines to a working stationcomprising a pumping means for application of adhesives to slides, and alifting means for lifting and placing of a cover slip on a slide whichis provided with adhesive, characterized in that the two magazines arelocated on opposite sides of the transport means, and that the transportmeans is arranged to carry a slide from the first magazine to theworking station in an outgoing movement from a home position, and tocarry a cover slip from the second magazine to the working station in areturn movement, the lifting means being arranged to lift a cover slipfrom the transport means before the latter is allowed to start itsoutgoing movement, and further is arranged to place a cover slip on theslide on the working station with terminated outgoing movement of thetransport means and after application of adhesive to the slide by thepumping means, the transport means being arranged to bring the slidewith attached cover slip back to the first magazine during its returnmovement, at the same time as a new cover slip is carried from thesecond magazine to the working station.
 2. A machine according to claim1, characterized in that it has a box-like shape and is divided into arearward closed main chamber and a forward main chamber by means of alongitudinally extending, vertical partition wall supporting most of thecomponents of the machine, the rearward main chamber containing as maincomponents a number of drive motors and electronics for operation andcontrol of the function of the machine, and the forward main chambercontaining as main components the two magazines, the transport means,the lifting means and the pumping means, and that the forward chamber atthe front is covered by a transport sliding door adapted to be liftedoff for maximum accessibility.
 3. A machine according to claim 1,characterized in that the pumping means is arranged to apply adhesive toa slide during the movement thereof when carried by the transport meansduring the outgoing movement thereof.
 4. A machine according to claim 1,characterized in that the cover slips magazine is a unit which isarranged for detachable mounting in the machine, with a view to rapidreplacement and introduction of other cover slips magazines dimensionedfor other cover slip sizes.
 5. A machine according to claim 4,characterized in that it is provided with sensors which sense thedimension of the cover slips magazine inserted in the machine, and whichprovide for possible readjustment of the control functions of themachine, for operation in accordance with the chosen cover slip size. 6.A machine according to claim 4, characterized in that the cover slipsmagazine is defined by a forward and a rearward end wall and a pair ofparallel side walls, and that it has an open bottom except for a pair ofedge flanges extending along the lower end edges of the side walls andforming a support for a stack of cover slips in the magazine, the edgeflanges having a somewhat lower level than a carrier plate on thetransport means and a mutual distance allowing introduction of a part ofthe carrier plate therebetween, the carrier plate being designed to gripand pull out a cover slip from the underside of the stack in its returnmovement from the magazine.
 7. A machine according to claim 6,characterized in that the carrier plate at its rearward end is providedwith an inclined plane for lifting of the cover slips stack in the coverslips magazine when introducing said part of the carrier plate in themagazine, and with a gripping edge adjacent to the inclined plane havinga height corresponding to the cover slip thickness, so that only onecover slip, which falls down in front of the gripping edge when thecarrier plate has been introduced in the magazine, is pulled out fromthe magazine in the return movement of the transport means.
 8. A machineaccording to claim 1, characterized in that the transport means isprovided with a sensing means to sense if a slide is present in afeed-out position in the slides magazine when the transport means is inits home position, and that the lifting means is arranged for lifting ofthe cover slip situated on the transport means under the presuppositionthat a slide is present in said position.
 9. A machine according toclaim 8, wherein the first magazine is arranged to receive at least onebasket having a number of shelves for support of slides, characterizedin that the sensing means is an electromagnet-operated gripping fingerfor gripping of a slide in the feed-out position, the gripping finger,if a slide is not present, under the influence of the electromagnetoperating a switch for start of a motor for stepwise feeding-down of thebasket in said magazine until the gripping finger senses that a slide ispresent in the feed-out position.
 10. A machine according to claim 9,characterized in that the lifting means comprises a suction cup meanswhich is connected to a twist cylinder coupled to a vacuum motor, thevacuum motor being arranged to start when the gripping finger hasgripped a slide in the feed-out position, to produce a vacuum in thetwist cylinder to retain the cover slip on the transport means againstthe suction cup means, there being provided a lifting motor providingfor lifting of the suction cup means with the cover slip from thetransport means when a vacuum is obtained.
 11. A machine according toclaim 9, characterized in that at least one of said motors, is adigitally controlled step motor, the motor being arranged to be operatedby means of pulses under the control of a processor unit.
 12. A machineaccording to claim 10, characterized in that the lifting motor iscoupled to the lifting means through an eccentric means causing thelifted cover slip, when the transport means has completed its outgoingmovement, to be lowered onto the slide with a sinusoidal movement, sothat the cover slip hits the glue with a relatively low speed.
 13. Amachine according to claim 1, characterized in that the pumping means isa cylinder/piston unit having a piston which is coupled to a pump motorthrough an eccentric means causing a symmetrical, slightly boat-shapedglue quantity to be pumped out from the cylinder onto the topical slide,with most of the glue in the middle and a decreasing glue quantity inthe direction towards the end edges of the slide.
 14. A machineaccording to claim 13, characterized in that one end of the pumpingmeans is connected to a glue container and the other end is connected toa glue dispenser which is fixed to the lifting means, the gluedispenser, when the lifting means is lowered, being placed with itsoutlet end if a fixedly mounted solvent container connected to the pumpcylinder and containing a solvent keeping the dispenser outlet open aswell as preventing the piston from being glued to the cylinder.
 15. Amachine according to claim 14, characterized in that the fixedly mountedsolvent container is connected via a hose connection to a detachablesolvent container for level control, filling and emptying of the fixedcontainer.